Multiple control of electric motors.



R. RICHTER.

MULTIPLE CONTROL OF ELECTRIC MOTORS.

APPLICATION FILED APR. 9, 1912.

I 1,080,587, Patented Dec.9,1913.

2 SHEETS-411KB! 1.

R. RICHTER.

MULTIPLE CONTROL OF ELECTRIC MOTORS.

v APPLICATION FILED APR. 9, 1912.

1,080,587, Patented Dec. 9, 1913.

2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

BUDOLF RICHTER, OF GR'fl'NAU, GERMANY, ASSIGNOR TO MAFFEI-SCHWABTZKOPFF4 WEBKE G. M. B. H., 01 BERLIN, GERMANY.

MULTIPLE CONTROL OF ELECTRIE! MOTORS.

Specification of Letters Patent.

} Patented Dec; 9, 1913.

Application filed April 9, 1912. Serial No. 889,589.

trol for Electric Motors, of which the following isa specificatiom IWhen separately fed electric motors, for example, the motors of severalindependent motor-driven vehicles of electric railways,

are to be controlled from one point, it 15 generally necessary toprovide means for insuring, that the single motors are-loaded accordingto their outputs.

Such an arrangement, which is of particularly simple character, whenthere are only two motors tobe controlled forms the subject matter ofthe present invention. According to this arrangement correspondingwinding parts of the motors to be controlled are connected with eachother by means of compensation leads, in such a manner, that thecurrent'in these compensation leads 1s at zero, when the motors areloaded according to this output; this means that the'motors as generallyused in practice are made uniform for then the same will when loadedallow the same output. Every difference in the absorption of power willthen cause a flow of current through the connecting influence thecontrolling members, relays and auxiliary motors in such a manner, thatthey will .a'gain restore the equality of the load on the motors.

In the present application under the term F. corresponding. windingparts of the different motors is meant such, winding parts thepotentialsof-which are substantially the same function of the power supplied tothe respective main motors or are approxi mately proportionate to theoutput, or such windings which vary according to the same law as'thatunder which the absorption ofpower varies. In general winding parts withproportional potentials will come into.

question. The most simple case is that, where the total windings of theindividual motors can be utilized, as for instance with.

motors of the same type and size.

In the accompanying drawing a construc-. tional form of the invention isexemplified.

Figure 1 shows the general arrangement in a diagrammatic form, whileFigs- 2 and 3 are modified arrangements of a 'part of the dlagram;

On the left hand'in Fig. 1 is shown an r ordinary series motor F asdriving motor, on the right hand side a motor F fed from two sources,for illustrating the application of the invention to diflerent types ofdriving motors. The energy is supplied to the .motors through thetransformers T, which again are fed from the feeder .line by means ofcollectors q. The other ends of the primary windings p of thetransiormers=are grounded. The leads connecting to the driving motors For F respectively are branched 011? at a and b respectively from thesecondary windings s of the transformers and marked in the drawing byheavy lines. They comprise besides the driving motors the secondarywinding 2' of an inductlon regulator orrotary transformer I,

which serves to regulate the electromotive force supplied to the drivingmotor. This isdone in the known manner by turning theprimary winding z"of the induction regulator, which is connected at '0 and r to thesecondary winding of the transformer T. The rotation of the inductionregulator is effected by means of a transmission gearing, indicated inthe drawing by the reference. letter m, from an auxiliary motor H. Theauxiliary motors have the form of ordinary series motors, being,however, provided with additional field windings h which connect in the.constructional form shown 'on the left hand side of the drawing, at nwith the driving motor F in theother constructional form with thesecondary windings .of two auxiliary transformers t 15 connected inseries. The total of the electromotive forces of these secondarywindings, the other ends of which are grounded at 0, represents thetotal electromotive force of the motor F fed from two sources,

which force corresponds to that of the series motor F, in other wordsthe series connected secondary windings are the windings of the'motor Ffed from two'sourcesfwhich total windings correspond to the totalwindingsof the motor F, the direct connection to the windings of themotor F not grounding between the points 0, 0.

being possible, owing to the fact that the number of turns in the statorand that in the rotor are not the same.

The primary sides of the auxiliary transformers t and t thetransformation ratio of which corresponds to the electromotive force ofthe motor F are connected to the field and the working windingsrespectively of the motor F and connected in series. The point ofconnection is is connected with the point of connection 9 for thecompensating lead to the transformer T. The'electromotive force at theauxiliary transformer 2?, which is constant, may also be taken from.

the secondary winding s of the main trans-v former T, (Fig. 3) in whichcaseonly one auxiliary transformer t is required.

used to denote the same parts as in Fig. 1. It will be seen that thearrangement is practicallythe samev as in Figfil excepting that theauxiliary transformer tand the leads corresponding; thereto are?dispensed with;

The other ends of the auxiliary windings 7L2" the secondary side of theauxiliary trans-' formers t t and. containing the additional fieldwinding 71. of the auxiliary motor H on the right, farther extendingthrough the connection lead e, the winding 72. of the left auxiliarymotor and continuing over point it andthe motor F to 0, and closed bythe The connections of the additional windings W, k are such that acompensating current, which will weaken the field of the one auxiliarymotor, will correspondingly increase the field of the other.

When the motors F and F are to be started, one of the switches d at thedrivers stands, which are connected by means of a lead Z, is closed; theother remains. open.-

The auxiliary motors H will then start and turn the induction regulatorI so that the total electromotive force supplied to the motoris-increased. As soon as this increase takes place for some reason'orother, more rapidly at one of the motors, than at the other, acompensating current flows throu h the windings k and strengthens thefie d of the corresponding control motor H, whereby the speed of thismotor is diminished, so that the increase of the electromotive force atthe res ective main motor is slowed down. The field of the other controlmotor on the other hand is weakened, and its speed is accordinglyincreased, the electromotive force supplied to the corresponding mainmotor will therefore rise In Fig. 3 the same reference characters aremore rapidly. V The smallest differences in the power absorption of themain motorsF and F are thus immediately compensated by a suitableactuation of the control motors.

The corrective working of the compensation currents take place the morepromptly,

the better the phase agreement between the tors even while theadditional field winding is unexcited, it is further advisable toprovide compensating connections between the armature winding and themain field winding of the control motors H so that the. ar-

mature electromotive forces on the other hand are all equal to eachother. The additional field windings h are preferably so arranged, thatthey are not ma netically interlinked with the main fie d windings. Theymay also be replaced by seriestransformers, the primary windings ofwhich are traversed by the compensation current and the secondarywindings of which are connected in series with the main field windingsof the control motors.

What I claim is:

1. In combination with a system for con trol of separately fed electricmotors from one place, means for individually regulating the voltage ofsaid motors, auxiliary motors for actuatingsaid regulating means,compensating leads connecting the windings of said auxiliary motors tocorresponding winding parts of the different main motors, the connectionofsaid compensating leads to the windings of said auxiliary motors beingsuch as to cause the currents flowing in said leads to strengthen thefields of said auxiliary motors for those motors absorbing too muchpower and to weaken the fields of the other auxiliary motors.

2. In combination with a system for the control of separately fedelectric motors from one place, means for individually regulating thevoltage of said motors, auxiliary motors for actuatingsaid regulatingmeans,

.said auxiliary motors, compensatin current traction system of the typehaving a main transformer on each locomotive along with a rotaryadditional transformer as voltage regulator for the driving motor,auxiliary motors for driving said rotary transformers, additional fieldwindings in leads containing said additional field windings andcorresponding winding'parts of the in-' dividual 7 main motors, theconnection of said compensating leads to said additional windings beingsuch as to cause the currents fiowin in said leads to strengthen thefields of said auxiliary motors for those motors absorbing too muchpower and to weaken the fields of the other auxiliary motors, switcheson each locomotive for supplying said auxiliary motors from thesecondaries of said main transformers, and leadsconnecting said switchesto each other.

4. In combination with an alternating current traction system of thetype having a main; transformer on each locomotive along with a rfotaryadditional transformer as voltage regulator for the driving motor,auxiliary motors for driving said rotary transformers, additional fieldwindings in said auxiliary motors, compensating leads containing saidadditional field windings and corresponding winding parts of the in- Idividual main motors, the connection of said compensating leads tosaidadditional windings being such as to cause the currents flowing in saidleads to strengthen the fields of said auxiliary motors for those motorsabsorbing too much-power and to weaken the fields of the other auxiliarymotors, switches on each locomotive for supplying said auxiliary motorsfrom the secondaries of said main transformers, leads connecting saidswitches to each other, and ohmic resistances inserted in saidcompensating leads in addition to said additional field windings.

5. In; combination with an alternating current traction system of thetype having a main transformer on each locomotive along with a rotaryadditional transformer as voltage regulator for the drivin motor,auxiliary motors for driving sai rotary transformers, additional fieldwindings in said auxiliary motors, compensatin leads containing saidadditional field windings and corresponding winding parts of theindividual main motors, the connection of said compensating leads tosaid additional windings being such as to cause the currents flowing insaid leads to strengthen'the fields of said auxiliary motors for thosemotors absorbing too much power and to weaken the fields of the otherauxiliary motors, switches on each locomotive for supplying saidauxiliary motors from the secondaries of said main transformers, leadsconnecting said switches to each other, and inductive resistances in thearmature circuits of said auxiliary motors.

6. In combination with an alternating current traction system of thetype having a main transformer on each locomotive along with a rotaryadditional transformer as voltage regulator for the driving motor,auxiliary motors for driving said rotary transformers, additional fieldwindings in said auxiliary motors, compensating leads containing saidadditional field windings and corresponding winding parts of theindividual main motors, the connection of said compensating leads tosaid additional windings being such as to cause the currents flowing insaid leads to strengthen the fields of said auxiliary'motors forthosemotors absorbing too much power and to weaken the fields of theother auxiliary motors, switches on each locomotive for supplying saidauxiliary motors from the secondaries of said main transformers, leadsconnecting said switches to each other, ohmic resistances inserted insaid compensating leads in addition to said additional field windings,and compensating connections between the points of connection of thearmature windings and main field windings of said auxiliary motors.

7. In combination with an alternating current traction system of thetype having a main transformer on each locomotive along with a rotaryadditional transformer as voltage regulator for the driving motor,auxiliary motors for driving said rotary transformers, additional fieldwindings in said auxiliary motors, compensatin leads containing saidadditional field windings and the windings of the main motors, theconnection of said compensating leads to said additional windingsbeingsuch as to cause the currents flowing in said leads to strengthenthe fields of said auxiliary motors for .those motors absorbing too muchpower and to weaken the fields of the other auxiliary motors, switcheson each locomotive for supplying said auxiliary motors from thesecondaries of said main transformers, and leads connecting saidswitches to each other.

8. In combination with an alternating current traction system of thetype having a main transformer on each locomotive along with a rotaryadditional transformer as voltage regulator for the driving motor,auxiliary motors for driving said rotary transformers, additionalfieldwindings in said auxiliary motors, compensating leads containing saidadditional field windings and the windings. of the main motors, theconnection of said compensating leads to said additional windings beingsuch as to I 10 tween the points 0 cause the currents flowing in saidleads to ture windings and main field windings of strengthen thefields-of said auxiliary mosaid auxiliary motors.

tors for those motors absorbing too much In testimony whereof I havesigned my power and to'wea'ken the fields of the other name to thisspecification in the presence of aauxiliarg motorlsg switohies on eachlocotwo subscribing witnesses.

motive or su p ing sai auxiliar motors from the sec nd aries of said mai trans- RUDOLF'RI-CYHTER' formers, leads connecting said switches toWitnesses:

each other and com ensating connections be- HENRY HAsPER,

f connection of the arma- WOLDEMAR Heur'r.

